There are some who take the view that things outside of the Church are able to be redeemed for God’s glory. So rather than condemning contemporary music, they believe we ought to redeem it for God. They use this reasoning in many areas where culture meets the Church from music, technology, movies, etc. There are others who feel contemporary music is only about the feelings and doesn’t uphold the tradition. To me this argument doesn’t hold as much water since if we are truly going to go by tradition why not go further back than hymns and masses? Furthermore if you look at Church music from the Renaissance and Baroque periods you often see the borrowing of melodies between secular music styles and Church music styles. Why? Because people knew the tunes and could participate. There are some who also view that all verses not directly quotable from the Bible and involving instrument accompaniment to not be true Church music.
Personally I think its a silly argument from a musical perspective because the Church has always been using the best composers at the time and latest forms of musical development from polyphony, four-part vocal harmony, key signatures, music forms like cantatas and oratios, etc. Its just a matter of when you want to say enough is enough by drawing the definitive line which differs between Churches and denominations. For me I prefer some good Palestrina or Monteverdi over contemporary Christian but I don’t view contemporary Christian as not Christian.